About 6 years ago I bought an Oppo 105 specifically to enjoy the so-called benefits of higher resolution SACDs/DVD-As. Turns out the 105 simply isn't that great for either SACD and especially Red book. Quite likely the transport is the biggest issue. Maybe 3 years ago I upgraded the IEC, and jumper to bypass the 110/220 switch, then replaced the power supply with an aftermarket all from Ebay. These made terrific improvements, but also pointed the finger at the transport being the chief culprit. A couple years ago I bought a Audio Alchemy DDP-1 + PS 5 and a Marantz HD CD-1 (player, but used only as a transport) to play Red book CDs and it way outperformed the 105 playing the same disc's SACD layer (using XLR outs into the DDP-1)! A couple months ago the Marantz died and I decided to get a dedicated transport (Audiolab CDT6000. I no longer use the 105, unless for a classical disc that I don't have a red book.
rapping it up, you need a high quality SACD player=$$$$$ to enjoy hi-rez benefits
hth